So final post for the day and its good news. I’ve surprised myself by getting it working. Checked the door switches and they’re fine, with some doubt took the headstock switch cover off and luckliy spotted a little steel shaft in the corner of the compartment. Figured out what it did, put it back in…fiddly, wired it all back up and hey presto it all appears to operate:
https://youtube.com/shorts/67N8NL4KBdw
Extremely grateful for all the very useful advice so far.